Revision da6fa7ef67f07108a1b0cb9fd9e7fcaabd39c051 authored by Yazen Ghannam on 03 April 2018, 14:02:28 UTC, committed by Thomas Gleixner on 26 April 2018, 14:06:19 UTC
Recent AMD systems support using MWAIT for C1 state. However, MWAIT will
not allow deeper cstates than C1 on current systems.

play_dead() expects to use the deepest state available.  The deepest state
available on AMD systems is reached through SystemIO or HALT. If MWAIT is
available, it is preferred over the other methods, so the CPU never reaches
the deepest possible state.

Don't try to use MWAIT to play_dead() on AMD systems. Instead, use CPUIDLE
to enter the deepest state advertised by firmware. If CPUIDLE is not
available then fallback to HALT.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Link: https://lkml.kernel.org/r/20180403140228.58540-1-Yazen.Ghannam@amd.com

1 parent 14d12bb
History
File Mode Size
Documentation
LICENSES
arch
block
certs
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format -rw-r--r-- 12.8 KB
.cocciconfig -rw-r--r-- 59 bytes
.get_maintainer.ignore -rw-r--r-- 31 bytes
.gitattributes -rw-r--r-- 30 bytes
.gitignore -rw-r--r-- 1.5 KB
.mailmap -rw-r--r-- 9.2 KB
COPYING -rw-r--r-- 423 bytes
CREDITS -rw-r--r-- 96.3 KB
Kbuild -rw-r--r-- 2.2 KB
Kconfig -rw-r--r-- 287 bytes
MAINTAINERS -rw-r--r-- 442.9 KB
Makefile -rw-r--r-- 61.0 KB
README -rw-r--r-- 800 bytes

README

back to top